I've been playing a lot of silksong, and even though a lot of the characters and enemies are drawn in a cute style and somebody unfamiliar with the game might think it's to appeal to kids, the whole atmosphere of that game is all somber, melancholic, maybe bittersweet, it's a dangerous world full of fleeting moments. A game needs to have at least some sort of artstyle, and if it's a cartoony one it can still be mature/realistic, I think you can have both and I love it when it happens! Take TTYD for example, part of why everybody loves it is because they didn't hold back with things like how rough rogueport is and even having a trans character because that's how the world is. Even Mother 3 has a character with a limp, and even though it has a cartoony style, it also constantly tugs on your heartstrings and always makes you think about what's going on in the story